The HomeFill II Oxygen Compressor system, available from Invacare Corporation of Elyria, Ohio, allows patients to fill their own high-pressure cylinders from a concentrator. The system includes a multi-stage pump that compresses oxygen from an oxygen concentrator into portable oxygen cylinders in sizes M6 and M9. This ability to fill their own portable cylinders gives ambulatory patients greater independence and freedom, and minimizes time-consuming and costly service calls associated with cylinder and/or liquid oxygen deliveries.
Systems of this type are shown in U.S. Pat. Nos. 5,998,165 and 6,302,107.